Unit 5: Lesson 3 Flashcards
biome
major life areas characterized by vegetation type or by their physical environment
Factors that determine biomes
- latitudinal patterns
- temperature
- precipitation
- climatic variation
- abiotic factors that affect what can grow
- organisms adapted to an environment
ecotone
an area of overlapping biomes
climograph
a plot of the annual mean temperature and precipitation in a particular region
vertical layers of a biome
- canopy
- lower-tree layer
- shrub understory
- ground layer of plants
- florest floor (litter layer)
- root layer
disturbance
an event that changes a community
- may remove organisms or alter resource variability
- results in biome patchiness
density
of individuals per unit area or volume
- ecologists may count a sample or indicators of a population size or use mark-recapture method
- dynamic
dispersion
pattern of spacing among individuals of a population
- clumped (due to environmental conditions, mating behavior, better defense or predation)
- uniform: (due to antagonistic behaviors between individuals; rare)
- random (independent positioning)
demography
the study of the vital statistics of populations and how they change over time
life tables
age-specific summary of the survival pattern of a population
-follows a cohort from life to death
cohort
a group of individuals of the same age
Reproductive tables
-measures reproductive output of a cohort from birth to death
Per Capita Rate of Increase Formulas
dN/dt= B-D= bN-mN= rN
N=pop size b= per capita birth rate m= per capita death rate
r=b-m
Exponential growth
growth of a population under ideal conditions
dN/dt= r(max)N
-may occur in drastically reduced or newly introduced populations
Density-Dependent Factors
-provide negative feedback needed to halt population growth Includes: -competition for resources -predation -intrinsic factors -toxic wastes -territoriality -disease
